P.s.i.

Pound per square inch
A pressure gauge reading in psi (red scale) and kPa (black scale)
Unit information
Unit system	Imperial units, US customary units
Unit of	Pressure, Stress
Symbol	psi or lbf/in2
Unit conversions
1 psi in ...	... is equal to ...
SI units	6.894757 kPa

The pound per square inch or, more accurately, pound-force per square inch (symbol: lbf/in²; abbreviation: psi) is a unit of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force of one pound-force applied to an area of one square inch:

${\displaystyle 1~{\text{psi}}={\frac {1~{\text{lbf}}}{(1~{\text{in}})^{2}}}\approx {\frac {4.4482~{\text{N}}}{(0.0254~{\text{m}})^{2}}}\approx 6894.757~{\text{N}}/{\text{m}}^{2}}$

Therefore, one pound per square inch is approximately 6894.757 Pa.

Now converting the psi to standard atmospheres: